The invention relates generally to microturbine systems for use in power generation and more specifically to microturbine systems having a recuperator mounted directly above a turbine.
Microturbine systems of the type described herein are used to generate electricity and heat for small or limited applications. A recuperated microturbine system includes a turbine, which feeds hot exhaust gas to a recuperator. The recuperator is a heat exchanger intended to improve the overall efficiency of the microturbine system.
A hot gas flows through the turbine and recuperator during operation. The flow of hot gas causes a substantial temperature increase in the turbine and recuperator. The change in component temperatures causes thermal expansion of the turbine and recuperator. An allowance must be made to accommodate this thermal expansion. A microturbine system that does not reasonably accommodate the thermal expansion of the turbine and recuperator is susceptible to distortion, high stress, and potential component failure. In addition, an adequate seal must be maintained between the turbine and recuperator to avoid the leakage of hot exhaust gas from the turbine. It is therefore important to provide a reliable means of accommodating the thermal expansion without leaking hot exhaust gas.
The present invention provides a support structure for the recuperator. The support structure includes a plurality of spring supports that permit thermal expansion between the turbine and recuperator.
The microturbine system includes a frame, a recuperator, and a turbine having a central axis, a mounting end coupled to the frame, and an exhaust end coupled to the recuperator. A plurality of springs are coupled to the frame and support the recuperator. Expansion or contraction of the turbine causes the recuperator to move in a direction parallel to the turbine central axis.
The plurality of spring supports include the springs, and a post coupled to the frame, the post having a longitudinal axis. The spring has a center axis substantially collinear with the post longitudinal axis, and a first end coupled to the frame. The spring has a second end in supporting contact with the recuperator. The spring supports allow thermal expansion to occur without creating high stress in the turbine or unduly restricting turbine movement. Thermal expansion of the turbine causes the turbine to lift the recuperator, partially de-compressing the springs.